Prop for trailers



March 7,1950 JJ. BLACK y 2,499,625

PROP FOR TRAILERS Filed July 4, 1944 2 Sheets-Sheet 1 March v7, 1950 J. J. BLACK 'PROP RoR TRAILERS Filed 'July 4, 1944 2 Sheets-Sheet 2 IN VEN TOR.

Patented Mar. 7, 1950 PROP FOR TRAILERS James J. Black, Cincinnati, Ohio, assigner to The Tralmobile Company, Cincinnati, Ohio, a corporation of Delaware Application July 4, 1944, Serial No.`43,501

3 Claims. 1,

This invention relates toy a prop or 'landing gear construction for supporting the front end of road vehicles, particularly a vehicle suoli as a semi-trailer, which is Ileft positioned for 'loading and unloading, after detachment from the tractor. The particular type of prop to which this invention relates is the manually operable type as distinguished from a. structurewhich is elevated and lowered automatically upon coupling and uncoupli-ng withthe tractor'.

More specifically this invention contemplates lcertain improvements in props of the telescoping,

tubular type.. Props of this type are strong and sure in their operation and comparatively easy to manipulate` However. by' their very design they are expensive to construct as they creusually made from cast steel tops with tubular bottoms. Also, the problem of supplying lubricant to the operative mechanism. is Aone which has always caused substantial diiculties.

Qne of the objects of vthe present. invention has been the provision of a prop construction which does not sacriiice strength or rigidity and yet is comparatively inexpensive to. build, being made in its enti-rely of pressed", rolled,v yand formed steel, except'. forv the actuating screw and related parts.

Another object `of they invention has been the provision of outer andr :inner tubular members i which are. square: in section for Vthe"purpf-)se of preventing rotation oef one member with respect to the other during raising or lowering of kthe extensible member'.

Still another objectof the invention is tov provide an enclosed gear box at they upper end of the outer tubular member so that thegear mechanism, which operates to raise or .lower the prop, can be packed, in grease.. The base. eithe gear box may be congurated so' asv to contain the. general thrust bearing along `with Yagree-se seal, means being provided to transmit grease from the grease bor:r to the thrust,- bearing and to other elements ot the. operative. mechanism housed in the lgear box.

Another object has been, to provide a vstructure in. which the upper surface of thevprcp may .be disposed almost directlyl againstI the. iloor of the trailer chassis so that the, prop tubes may be of maximum length for providing the. greatestpossible adustment range.

Another ohiect, of this prop is to provide actuating means for changing the reductionratio to accommodate the, operation to dierent types of. loadsjlited 'byy the; propaml' for adusting the 'lifting speed yto the weight ofthe load; a high speed being provided when the load is light and a low speed when the load is substantial.

Another object has been to provide a `novel arrangement adapted to provide continuous lubrication to the nut and screw mechanism.

Other and further objects and advantages will be apparent from the further and more detailed description of `a preferred embodiment of the invention when considered in conjunction with the drawings, in which:

Figurel is a front elevation of a structure of the preferred type of the invention in operative position on a semi-trailer body.

Figure 2 is a cross sectional View through one of the telescoping, tubular prop assemblies.

Figure 3 is a sectional plan view taken along the line 3-3 of Figure 2.

Figure 4 is a fragmentary elevational view of the -prop actuating means.

In Figure 1, a semi-trailer body of conventional construction is illustrated fragmentarily at Ill. The longitudinal channel members of the chassis are indicated at `I l--H and the outer rail of the chassisy at l2.

In the construction of the props a pair of telescoping, tubular post assemblies are disposed in av vertical position on the underside of the trailer body and arey designated generally at i3. These postassemblies are kstrong and rigid and carry plates ld Welded to one side, toward the top there of which provide connecting means to the longitudinal channel members H. This connection may be made by bolts, welding or in any conventional Way.

Each tubular assembly' i3 is ycomprised of a pair* of telescoping, tubular members l5 and Hi, the outer member being designated i5 and the inner member It. Both tubes are square in sec tion (Figurey 3) to prevent rotation of one. in re.- lation to the other during elevating or lowering. The gearbox l1 at the upper end of the outer tubular member i5 is formed by welding Aa base la into the tube and by fastening a top I9 on the uppermost portion of the outer tube so that the ygear mechanism, which will be described subsefquently, can be packed in grease and lubricae tion maintained for a considerable period of time.

The inner tubular post l5 is retractable with respect to the outer post l5 by means of a rotatable sleeve. 13 (Figure 2)- Which .is mounted within. the retractable postitv and driven by bevel gears. Theretractable post It is connected to the rotatable sleeve. by an elongated stationary screw T0 extending upwardly and'threaded into a nut 'I5 at the lower end of the rotatable sleeve so that, upon rotation of the sleeve, the retractable post is raised or lowered. A novel and advantageous arrangement for supplying lubricating oil to the rotatable sleeve from a reservoir at the lower end of the retractable post I6 is later described in detail. The upper end of the rotatable sleeve T3 is provided with a stud I4 journalled in a bushing- 22 confined in the base I8 of the gear box. Keyed to the upper end of stud 14, as at 23, is a bevel gear 24 which is held in position between a washer 25 and a snap ring 26 engaged in a groove at the upper extremity of the stud. The gear box base I8 is counterbored from the underside, as at 28, to receive the general thrust bearing 29 and provide a grease seal. Lubrication bores 33 extend diagonally through the base of the gear box and the bushing 22 to supply grease to the thrust bearing and to the bushing.

The upper end of sleeve 'I3 includes a shoulder I6 seated against the thrust bearing 29. On its outer circumferential face, adjacent the shoulder 16, the sleeve 'I3 is grooved as at TI, to carry a packing gland 'I8 which forms a grease seal for the gear box and thrust bearing. The actuating screw 'I0 engages the nut 'I5 at the lower end of the sleeve 'I3 and extends upwardly into the sleeve a substantial distance when the prop is in fully retracted position as illustrated in Figure 2. To facilitate the assembly of the structure, the sleeve is provided with apertures 'IQ-19 adjacent its upper extremity to allow a stop pin 8D to be inserted in the upper end of the screw 'I0 after the screw is threaded through the nut. The stop pin limits the downward travel of the retractable post I6, thus preventing any possibility of the post being extended downwardly until it becomes disengaged from the outer post I5.

A cross shaft 34 extends horizontally through the side walls 35-35 of the outer tube I5 toward the top thereof and carries a bevel gear 35 keyed thereto internally of the gear box and adapted to mate with the bevel gear 24 fixed to the vertical sleeve stud 14. The cross shaft 34 is journalled in bushings 38-38 welded to the outside of the side walls 35 of the outer tube and is held in position by means of collars 39-39 pinned to the shaft adiacent each bushing 38.

As is readily apparent from the preceding description of the prop structure it is possible to place the upper portion of the prop almost directly against the oor of the trailer chassis so that both the outer and inner tubes are of a length sufficient to provide a maximum adjustment range. With this arrangement the extension of the cross shaft to the exterior of the vehicle frame would ordinarily pass through the outer rail I2 thereby making it impractical to use a conventional crank. Therefore, a universal joint 46 is applied on the side adjacent the outer Yllearing of the cross shaft and a shaft 4I extends from this joint angularly and downwardly under the outer rail I2, the crank 42 being pivotally carried at the outer end of this shaft. As illustrated in Figure 1, when not in use the crank 42 vis swung inwardly and upwardly to a position substantially parallel with the shaft 4D and is held in this position by means of a clip 43. On its inner end the cross shaft is fixed to a pipe 44 by means of a bolt 45. This pipe extends across the underside of the trailer chassis and connects with the cross shaft of the opposite prop to operably .ioin the two. Since the two props. are identical the construction and operation has been described in the singular throughout this specification.

As the handle is rotated the cross shafts 34 of the props are actuated by means of the shaft 4I and the pipe 44. Each bevel gear 36 being keyed to its respective cross shaft 34 actuates a sleeve 'i3 by means of a bevel gear 24. In the position shown in Figure 2, the inner tube I6 is in its elevated position with respect to the outer tube I5.

An inverted U-shaped member 52, welded to the lower extremity of the inner tube. provides a closure for the end and also provides a bracket for a conventional set of rocking prop wheels 53.

f The axle 54 for the wheels is centrally cross bored as at 55 to provide a center bearing and has its ends turned to provide spindles for the wheels 53. Interposed between the axle 54 and an axle cross shaft 56 is a steelbound rubber bushing 51. This bushing eliminates metal-to-metal shock if the prop is not completely extended before uncoupling takes place.

In Figure 4 is illustrated a crank mechanism in which a pair of sprockets 58 and 59 are pinned to the outer end of the cross shaft 34. A sliding crank carrying shaft 5D is journalled in bosses 6 I-SI provided by a bracket G2 fixed to the outer tube I5. This shaft lies in a plane considerably below the plane of the cross shaft and is substantially parallel therewith. Disposed on the crankshaft 65 between the bosses BI-EI is a pair of floating sprockets 63 and 64 adapted to be operably connected to the sprockets 58 and 59 respectively by chains 55 and 56. A clutch pin 51 fixed in the crankshaft extends outwardly into mating T-slots 68 and 59 provided in the bosses of the sprockets 53 and 64 and is adapted to engage either of these T-slots. Utilizing this arrangement, and employing sprockets of different sive as illustrated in Figure 4, it is possible to attain a comparatively high speed for the raising operation when the load to be lifted is light and a comparatively low speed when the load is substantial. It is also possible to omit the outer sprockets 58 and 53 on the two shafts and to pin the sprocket 54 to the crankshaft to provide only one set of mating sprockets connected by the chain 66. Bv this method it is possible to provide a permanent reduction ratio particularly adapted to the function of each particular vehicle. In each of these modications the universal ioint may be omitted since its function is supplied by the sprocket arrangement.

The lower portion of the inner tube i6 constitutes an oil reservoir for the actuating screw and nut which in coniunction with the rotatable sleeve 13 lubricates the sleeve and nut automatically upon actuation of the prop to promote ease of operation. The cooperation between the rotatable sleeve and the oil reservoir is an important feature of the present invention since it assures adequate and continuous lubrication of the sleeve' and screw for prolonged periods of service without replenishment of the oil supply and thus improves greatly the performance of the structure. Apertures 8I-8I in the tubular member 73 adjacentthe upper extremity of the nut '15 are provided to supplv oil to the screw and .screw as it commences to engage the nut 15. Upon raising of the prop, the oil containedin the reservoir reenters the apertures l-i to replenish the supply in the tube 73. An aperture S2 in the side wall of the inner tube i6 prevides filler means for the oil reservoir. A cap screw 93 is threaded into a boss t4 welded about inner peripheral edge of the aperture 32.

Each time the retractable member i9 is elevated to the position shown in Figure 2, a fresh charge of oil iiows through the openings 8l and is trapped within the sleeve to lubricate the full length of the screw 19 when the post i9 again is adjusted to its extended position. The cil which is thus trapped above the nut adheres naturally to the screw threads as the nut rotates in the direction to lower the post. By virtue o t the fact that the oil is sealed within the retractable post, the oil is kept free from contamination by dirt and retains its lubricating eiciency almost indenitely. Any metallic particles which in the course of service may become commingled with the oil, will settle to the bottom of the reservoir, while clean oil for lubricating the screw and nut is drawn from the upper level of the reservoir. The structure thus supplies oil in a dependable fashion where it is most needed and stores a copious supply in reserve so that very little servicing is necessary.

Having described my invention, I claim:

1. A. prop for trailers comprising two tubular telescoping members, one of said members being xed to the trailer and the other of said members being extensible and carrying wheels for supporting the trailer, an actuating screw rigidly secured within the extensible member in vertical position, an inner tubular member enclosing said actuating screw, a portion of said inner tubular member forming a nut for engagement with the screw, another portion of said inner tubular member being spaced from the screw and from the inner wall of the extensible member and having a port formed therein whereby oil contained in the extensible member will pass into the inner tubular member for lubricating the nut and screw, means for supporting the inner tubular member with respect to the trailer body and means for rotating the inner tubular member for raising and lowering the extensible member.

2. An elevating mechanism for the forward end of a semi-trailer comprising; a stationary hollow post depending from the trailer frame, an elongated rotatable sleeve mounted within said stationary post, said rotatable sleeve having an elevating nut disposed at its lower end, means mounted on the trailer frame for rotating the sleeve and nut, a retractable hollow post telescoped relative to the stationary post, a lubricant reservoir disposed Within said retractable post, an

elevating screw extending upwardly from the bottom of said reservoir, said elevating screw threaded through said elevating nut whereby rotation of the elongated sleeve and nut translates the screw through the nut to raise and lower the retractable post, the rotatable sleeve having an aperture above the elevating nut whereby lubricant in the reservoir flows inwardly through said aperture to immerse the portion of the screw within the rotatable sleeve when the retractable post is in elevated position and flows outwardly through the aperture as the post is moved to extended position.

3. An elevating mechanism for the forward end of a semi-trailer comprising; a stationary hollow post depending from the trailer frame, an elongated rotatable sleeve dispcsed within the hollow post and substantially coextensive in length with the hollow post, said rotatable sleeve having an elevating nut disposed at its lower end, means at the upperend of the stationary post for rotating said sleeve and nut, a retractable hollow post non-rotatably telescoped within the stationary post, a lubricant reservoir disposed within said retractable post, means securing the bottom of the reservoir to the extensible member, an elevating screw extending upwardly from the bottom of the reservoir and substantially coextensive in length with the retractable post, said elevating screw threaded through said elevating nut whereby rotation of the nut translates the screw through it to raise and lower the retractable post, the said rotatable sleeve having an inside diameter which is greater than the diameter of the screw to provide an oil trap surrounding the screw, the said rotatable sleeve having an aperture above the elevating nut whereby the lubricant in the reservoir flows into the trap above the nut when the retractable post is in elevated position.

JAMES J. BLACK.

REFERENCES CITED The following references are of record in the ile of this patent:

UNITED STATES PATENTS Number Name Date 1,303,240 Berry May 13, 1919 1,387,563 Stawicki Aug. 16, 1921 1,635,689 Rauch July 12, 1927 1,659,785 Rodman Feb. 21, 1928 2,183,367 Fow Dec. 12, 1939 2,232,187 Reid Feb. 18, 1941 2,246,588 I-Iarrall June 24, 1941 2,348,869 Wagner May 16, 1944 

